1.Definition: having a smooth, gleaming surface reflecting light
"Slick seals and otters"
2.Definition: having only superficial plausibility
"A slick commercial"
3.Definition: made slick by e.g. ice or grease
"Sidewalks slick with ice", "Roads are slickest when rain has just started and hasn't had time to wash away the oil"
4.Definition: marked by skill in deception
"A slick evasive answer"
5.Definition: superficially impressive, but lacking depth and attention to the true complexities of a subject
"A slick advertising campaign"